Stabilized liquid compositions

ABSTRACT

A stabilized liquid composition containing an m-biscarbamate, for use as a herbicide.

United States Patent 1 1 Freund et al.

Aug. 5, 1975 STABILIZED LIQUID COMPOSITIONS Filed: July 3, 1972 Appl.No.: 268,882

Related US. Application Data Continuation of Ser. No. 4,420, Jan. 20,19,70, abandoned.

US. Cl 71/111; 71/D1G. 1 Int. Cl A0ln 9/20 Field of Search 71/111, DIG.1

References Cited UNITED STATES PATENTS Jones 71/117 Wilson et a1.....71/11] Payne et al. 71/111 Boroschewski.. 71/111 Albrecht 71 /D1G. 1

Primary Examiner.lames 0. Thomas, Jr.

ABSTRACT A stabilized liquid composition containing an mbiscarbamate,for use as a herbicide.

5 Claims, N0 Drawings STABILIZED LIQUID COIVIPOSITIONS This is acontinuation of application Ser. No. 4,420 filed Jan. 20, 1970, nowabandoned.

This invention relates to the stabilizing of liquid compositionscontaining m-biscarbamates by the addition of organic acids.

It is known that biscarbamates of the formula wherein R is alkyl,cycloalkyl, aryl which may be substituted by halogen and/or alkyl and/ortrifluoromethyl; R is hydrogen or alkyl; R and R jointly with the N-atom may form a heterocyclic ring which may contain additional N and/oratoms; and R is alkyl, alkenyl or alkinyl which may be m-substitutedwith halogen, have good herbicidal properties; as indicated in BelgianPat. No. 679,283.

Among these active agents, particularly, those in which R is hydrogen,they have practical application: for example,3-methoxycarbonylaminopheny1-N-3- methylphenylcarbamate. They areusually employed in the form of liquid compositions whose essentialingredients include at least one organic solvent and at least onesurfactant in addition to the active agent.

It is a disadvantage of such liquid compositions that they are notsufficiently stable and decompose either slightly or fully duringstorage. As a consequence, the concentration of active agent changes,and the composition loses its effectiveness.

It is known from U.S. Pat. No. 2,954,396 to stabilize N-substitutedalkylcarbamates against hydrolytic decomposition. Acetic acid,phosphoric acid, hydrochloric acid, ammonium dihydrogen phosphate,ammonium chloride, ferric chloride and mixtures of these compounds wererecommended as stabilizers.

As far as these stabilizers are soluble in the liquid compositionscontaining m-biscarbamates, they do not or do not adequately stabilizethe afore-mentioned liquid compositions.

It has now been found that liquid compositions containing at least onecompound of the formula wherein R is alkyl, cycloalkyl, aryl which maybe substituted by halogen and/or alkyl and/or trifluoromethyl; R ishydrogen; and R is alkyl, alkenyl or alkinyl which may be1.0-substituted by halogen, may be strongly stabilized by the additionof at least one organic acid from the group of aliphatic dicarboxylicacids, aliphatic hydroxycarboxylic acids, nitro substituted aromaticmonocarboxylic acids, aromatic dicarboxylic acids, aliphatic sulfonicacids and aromatic sulfonic acids.

These addition agents have good stabilizing effects in concentrations ofabout 0.05 to 5 percent by weight, and preferably 0.25 to 1.0 weight percent. Loss of efficacy during extended storage of the liquidcompositions is thereby largely avoided over extended periods or atleast strongly reduced.

Particularly suitable stabilizing agents include: oxalic, malonic,maleic, glycolic, lactic, citric, phthalic, 5-nitro-isophthalic,Z-nitrobenzoic, 3,5-dinitrobenzoic, 4-chloro-3-nitrobenzoic, 2-ch1oro-3,5-dinitr0benzoic, methanesulfonic, benzenesulfonic,p-toluene-sulfonic, and tetrapropylenebenzenesulfonic acids.

The liquid compositions to be stabilized have the usual formulationcustomary in crop protecting agents. The following ingredients aretypical: 0

1. Compounds of the above formula, particularly 3-methoxycarbonylaminophenyl-N-3-methylphenylcarbamate as the activeagent.

2. Solvents, such as aromatic hydrocarbons, cyclohexanone, isophorone,methylhexahydronaphthalene, dibutyl phthalate, tetrahydronaphthalene,dimethylsulfoxide and dimethylforrnamide.

3. Surfactants such as polyethoxylated amines, alcohols, acids and alkylphenols and salts of alkylated benzene and naphthalenesulfonic acids.

The quantitative formula of the liquid compositions is approximately asfollows:

5 to 50, preferably 10 to 25% (weight) active agent,

10 to 90, preferably 50 to (weight) solvent,

2 to 40, preferably 10 to 25% (weight) surfactant.

The stabilized liquid compositions are employed as herbicides forcontrolling undesired plant growth. The herbicide compositions excelparticularly for selective control of weeds in certain crop plants, suchas sugar, beets and rice, etc. The stabilizers proposed according to theinvention do not produce harmful effects of any kind. Furthermore, theliquid compositions may be prepared by simply mixing the afore-describedingredients.

The following Examples further illustrate the invention. In theseExamples, percentage figures are by weight.

EXAMPLE 1 Liquid compositions were prepared as follows:

12.5% 3-methoxycarbonylamino-phenyl-N-3- methylphenyl-carbamate;

15.8% emulsifier (a mixture of 'alkylbenzenesulfonate, polyethoxylatedfatty acid and polyethoxylated alkylphenol);

2.3% mixed high-boiling, aromatic hydrocarbons;

68.4% isophorone;

1.0% stabilizer.

The compositions were stored in glass bottles at +70C. After the periodsindicated in the following Table, samples were withdrawn and subjectedto thin layer chromatography. 1n the Table, indicates no visiblcdecomposition of the active agent 10% decomposed), and indicates clearlyvisible decomposition.

TABLE after after after Stabilizer 7 days 14 days 40 days No'additionOxalic acid Malonic acid Maleic acid Glycolic acid Lactic acid Citricacid Phthalic acid 'Nitro-isophthalic acid 2-Nitrobenzoic acid3,5-Dinitrobenzoic acid 4-Chloro-3-nitrobenzoic acid2-Chloro-3,S-dinitrobenzoic acid Methanesulfonic acid Benzenesulfonicacid p-Toluenesulfonic acid Tetrapropylenebenzenesulfonic acid Accordingto U.S. Pat. No. 2,954,396 above indicated: Phosphoric acid AceticacidEXAMPLE 3 Analogous results were also obtained by using the followingcompounds: 3-methoxycarbonylaminophenyl- N-phenyl-carbamate;3-ethoxycarbonylaminophenyl- The stabilizers listed below were added toa liquid N-3-methylphenylcarbamate; 3-ethoxycarbonylaminophenyl-N-phenylcarbamate; 3- composmon of thefollowmg mgred'enisi methoxycarbonylaminophenyl-N-3-chlorophenylcar-167% 3'ethoxycarbonylammophenyl'N'3' bamate;3-ethoxycarbonylaminophenyl-N-3- methylphenylcarbamatechlorophenyl-carbamate; 20.9% emulsifier (as in Example 1)methoxycarbonylaminophenyl-N-n-butyl-carbamate; 4.2% mixed,high-boiling, aromatic hydrocarbons3-methoxycarbonylaminophenyl-N-tert.butyl- 54.0% isophorone carbamate;3-methoxycarbonylaminophenyl-N-sec.butyl-carbamate;3-methoxycarbonylaminophenyl-N- pentyl-( 2 )-carbamate;methoxycarbonylaminophenyl-N-neopentylcarbamate;3-methoxycarbonylaminophenyl-N-( 3 ,5- dimethylphenyl)-carbamate.

EXAMPLE 2 Increasing amounts of stabilizer were added to a liq- Thecompositions were stored at 55 and 70C. Samples were drawn after thetime indicated and subjected to thin layer chromatography. In the table,indicates no visible decomposition of the active agent, indicates weakvisible decomposition of the active agent, and strong visibledecomposition of the active agent.

uid composition of the following ingredients: TABLE 1 6.4%3-methoxycarbonylaminophenyl-N-3- methylphenyl-carbamate 20.0%emulsifier (as in Example 1) Stabilizer T fi r fit? after 3.6% mixed,high-boiling, aromatic hydrocarbons dys dys 0 days 60.0% isophorone Noaddition C r stored at the temand the stabil zed compositions we e 1%malonic acid 55C peratures indicated. Samples were drawn at the timeslisted in the Table, and the degree of decomposition of l% male! acld iI i the active agent was determined quantitatively.

TABLE after after after after Stabilizer Temp. 14 days 28 days 40 days90 days No addition 20C 5% 10% 50C 20% 35% 45% 70% 70C 100% 0.25% citricacid 20C 0% 0% 70C 0% 0% 0.5% citric acid 20C 0% 0% 0% 70C 0% 0% 0% 1.0%citric acid 20C 0% 0% 0% 70C 0% 0% 0%- 0.5% malonic acid 20C 0% 0% 0%70C 0% 0% 5% 1.0% malonic acid 20C 0% 0% 0% 0% 70C 0% 0% 0% 10% 0.5%3,5-dinitrobenzoic acid 20C 0% 0% 0% I 70C 0% 0% 5% 1.0% 3,S-dinitrobenzoic acid 20C 0% 0% 0% EXAMPLE 4 The stabilizers listedbelow were added to a liquid composition of the following ingredients: I

16.7% 3-ethoxycarbonylaminophenyl-N-phenylcarbamate 31.7% emulsifier (asindicated in Example 1 33.3% isophorone 4.2% dibutyl phthalate 1.6%methylhexahydronaphthalene 12.5% tetrahydronaphthalene The compositionswere stored at 55 and 70C. Samples were drawn after the periods listedand were subjected to thin layer chromatography. The meaning of is asthe same as in Example 3, above.

TABLE after after after Stabilizer Temp. 7 days 14 days 40 days Noaddition 55C 70+C 171 malonic acid 55C 70C 1% lactic acid 55C EXAMPLE 5Increasing amounts of malonic acid were added to a liquid composition ofthe following ingredients:

1 2.5% 3-methoxycarbonylaminophenyl-N-3- methylphenyl-carbamate 15.8%emulsifier (as in Example 1) 3.3% mixed, high-boiling, aromatichydrocarbons 68.4% isophorone The mixtures so obtained were stored at20, 55 and 70C. Samples were taken after the periods listed andsubjected to thin layer chromatography. have the same meaning as above.

TABLE after 40 days after 14 days after Stabilizer Temp. 7 days Noaddition 20C 55C 70C 20C 55C 70C 20C 55C 70C 20C 55C 70C 20C 55C 70C 20C55C 0.1% Malonic acid 0.25% Malonic acid 0.5% Malonic acid 1.0% Malonicacid 2.0% Malonic acid TABLE-Continued after after after StabilizerTemp. 7 days 14 days 40 days 5 70C 5.0% Malonic acid 20C 55C 70C EXAMPLE6 The stabilizers listed below were added to a liquid composition of thefollowing ingredients:

16. 7% 3-methoxycarbonylaminophenyl-N-phenylcarbamate 20.4% emulsifier(as indicated in Example 1) 58.3% isophorone 4.6% dimethylsulfoxide Themixtures so obtained were stored at 55 and 70C in a comparison test witha control without stabilizer. Samples were taken after the periodslisted and subjected to thin layer chromatography. In the Table, havethe meaning given above.

TABLE after after I after Stabilizer Temp. 7 days 14 days 40 days Noaddition 55C 70C 3O 1% Malonic acid 55C EXAMPLE 7 35 EXAMPLE 8 In aliquid composition prepared from: 1 6.4%3-methoxycarbonylaminophenyl-N-3- methylphenyl-carbamate 20.0%emulsifier (mixture of alkylbenzenesulfonate,

polyethoxylated castor oil and polyethoxylated alkylphenol) 3.6% mixed,high-boiling, aromatic hydrocarbons 60.0% isophorone 0 a portion of thesolvent was replaced by varying amounts of citric acid as a stabilizer.The mixtures so obtained were stored four months at C and werethereafter analyzed quantitatively for decomposition of the activeagent. In samples containing 0.05% to 5.00% citric acid, nodecomposition was found. A control sample without stabilizer wasdecomposed.

What is claimed is: 1. In a herbicidal liquid composition consistingessentially of (a) a herbicidal compound having the formula:

carboxylic acids, aromatic dicarboxylic acids, aromatic sulfonic acids,and aliphatic sulfonic acids.

2. A composition of claim 1 wherein the organic acid is selected fromthe group consisting of slycollic acid, lactic acid, citric acid,phthalic acid, S-nitroisophthalic acid, Z-nitrobenzoic acid,4-chloro-3,5-dinitrobenzoic acid, metanesilfonic acid,2-chloro-3,S-dinitrobenzoic acid, benzenesulfonic acid, p-toluenesulfonic acid, and tetrapropylenebenzenesulfonic acid.

3. A composition according to claim 2 wherein the organic acid ispresent in an amount from about 0.25% to about 1%, by weight.

4. A method for stabilizing liquid herbicidal compositions as defined inclaim 1 by incorporating therein at least one organic acid stabilizeraccording to claim 1 in an amount of from about 0.05% to about 5%.

5. A method according to claim 4 wherein the organic acid stabilizer isselected from the group defined in claim 2.

1. IN A HERBICIDAL LIQUID COMPOSITION CONSISTING ESSENTIALLY OF (A) AHERBICIDAL COMPOUND HAVING THE FORMULA:
 2. A composition of claim 1wherein the organic acid is selected from the group consisting ofslycollic acid, lactic acid, citric acid, phthalic acid,5-nitroisophthalic acid, 2-nitrobenzoic acid,4-chloro-3,5-dinitrobenzoic acid, metanesilfonic acid,2-chloro-3,5-dinitrobenzoic acid, benzenesulfonic acid, p-toluenesulfonic acid, and tetrapropylenebenzenesulfonic acid.
 3. A compositionaccording to claim 2 wherein the organic acid is present in an amountfrom about 0.25% to about 1%, by weight.
 4. A method for stabilizingliquid herbicidal compositions as defined in claim 1 by incorporatingtherein at least one organic acid stabilizer according to claim 1 in anamount of from about 0.05% to about 5%.
 5. A method according to claim 4wherein the organic acid stabilizer is selected from the group definedin claim 2.